19 results on '"Clark, Nathan"'
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2. Safety of direct oral anticoagulant use in patients taking verapamil or diltiazem.
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Teshima, Samantha S.M., Casanova, Elsie M., Drees, Erin T., Clark, Nathan P., Hui, Rita, Niu, Fang, Pontoppidan, Kimi, Ekmekdjian, Hasmig, and Delate, Thomas
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- 2023
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3. Seeing through the clouds: Processes and challenges for sharing geospatial data for disaster management in Haiti.
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Clark, Nathan and Guiffault, Flore
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This article examines the ways in which the production and sharing of geospatial data for disaster management purposes have evolved in Haiti, within the context of the 2010 earthquake and 2016 Hurricane Matthew. The conditions for these developments are traced through the institutional and operational dynamics among key stakeholders at international, State and local levels. The article is presented as a case study and is based on reports, field observations and interviews with relevant stakeholders. Overall, the article finds that the increasing recognition, use and value of data for disaster management activities since the earthquake, is contributing to a number of interrelated economic, technical and legal processes and challenges for data sharing among stakeholders in the country. Economic findings are primarily centered around the impact which donor funding, project based work and “new market” dymnamics are having on data sharing. These issues feed into technical findings, where the increasing number of stakeholders and geospatial based projects has led to data access uncertainty and quality concerns among stakeholders. Lastly, legal findings are generally concerned with uncertainty regarding license conditions. Underlying each of these findings is the increasing value and implication of open data. The article concludes with an analytical discussion which frames these main findings within broader developments taking place in the global disaster management sector. [ABSTRACT FROM AUTHOR]
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- 2018
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4. Predictors of perioperative major bleeding in patients who interrupt warfarin for an elective surgery or procedure: Analysis of the BRIDGE trial.
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Clark, Nathan P., Douketis, James D., Hasselblad, Vic, Schulman, Sam, Kindzelski, Andrei L., Ortel, Thomas L., and BRIDGE Investigators
- Abstract
Background: The use of low-molecular weight heparin bridge therapy during warfarin interruption for elective surgery/procedures increases bleeding. Other predictors of bleeding in this setting are not well described.Methods: BRIDGE was a randomized, double-blind, placebo-controlled trial of bridge therapy with dalteparin 100 IU/kg twice daily in patients with atrial fibrillation requiring warfarin interruption. Bleeding outcomes were documented from the time of warfarin interruption until up to 37 days postprocedure. Multiple logistic regression and time-dependent hazard models were used to identify major bleeding predictors.Results: We analyzed 1,813 patients of whom 895 received bridging and 918 received placebo. Median patient age was 72.6 years, and 73.3% were male. Forty-one major bleeding events occurred at a median time of 7.0 days (interquartile range, 4.0-18.0 days) postprocedure. Bridge therapy was a baseline predictor of major bleeding (odds ratio [OR]=2.4, 95% CI: 1.2-4.8), as were a history of renal disease (OR=2.9, 95% CI: 1.4-6.0), and high-bleeding risk procedures (vs low-bleeding risk procedures) (OR=2.9, 95% CI: 1.4-5.9). Perioperative aspirin use (OR=3.6, 95% CI: 1.1-11.9) and postprocedure international normalized ratio >3.0 (OR=2.1, 95% CI: 1.5-3.1) were time-dependent predictors of major bleeding. Major bleeding was most common in the first 10 days compared with 11-37 days postprocedure (OR=3.5, 95% CI: 1.8-6.9).Conclusions: In addition to bridge therapy, perioperative aspirin use, postprocedure international normalized ratio >3.0, a history of renal failure, and having a high-bleeding risk procedure increase the risk of major bleeding around the time of an elective surgery/procedure requiring warfarin interruption. [ABSTRACT FROM AUTHOR]- Published
- 2018
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5. Towards a standard licensing scheme for the access and use of satellite earth observation data for disaster management.
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Clark, Nathan E.
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EMERGENCY management , *SATELLITE earth stations industry , *ACCESS control , *FLOODS , *HAITI Earthquake, Haiti, 2010 - Abstract
This paper explores from the view of the data recipient and user the complexities of creating a common licensing scheme for the access and use of satellite earth observation (EO) data in international disaster management (DM) activities. EO data contributions in major disaster events often involve numerous data providers with separate licensing mechanisms for controlling the access, uses, and distribution of data by the end users. A lack of standardization among the terminology, wording, and conditions within these licenses creates a complex legal environment for users, and often prevents them from using, sharing and combining datasets in an effective and timely manner. It also creates uncertainty among data providers as to the types of licensing controls that should be applied in disaster scenarios. This paper builds from an ongoing comparative analysis of the common and conflicting conditions among data licenses that must be addressed in order to facilitate easier access and use of EO data within the DM sector and offers recommendations towards the alignment of the structural and technical aspects of licenses among data providers. [ABSTRACT FROM AUTHOR]
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- 2017
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6. Unravelling dynamics of vulnerability and social media use on displaced minors in the aftermath of Italian earthquakes.
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Bonati, Sara, Nardini, Olga, Boersma, Kees, and Clark, Nathan
- Abstract
The uses of social media technologies in disaster risk management have been increasing in recent years, and a high number of studies have been produced with the purpose to investigate how social media can support disaster risk management processes. However, some criticalities in the use of social media, especially connected to limitations to accessibility, representativeness capacity, and the risks of disinformation and surveillance, have emerged and need to be further investigated. Accordingly, this work offers a critical analysis on how social media can impact post-disaster vulnerability, but also how it can be used as a tool for resilience by vulnerable people. In particular, the paper focuses on the challenges to which displaced minors have to deal with in post-disaster settings, following a series of large earthquakes which struck central Italy in 2016 and 2017. The results show that virtual space, and especially social media, is used by displaced minors to deal with the transformations that occur to the physical spaces of sociality. The virtual space becomes a potential source of resilience to help reconnecting with places and communities and working as a potential space of catharsis. The study is based on a series of semi-structured and in-depth interviews that took place in Italy between 2021 and 2022. The interviews involved participants with experience in disaster risk management in Italy, as well as with direct experience in the response and recovery efforts for the 2016–2017 Italian earthquakes. [ABSTRACT FROM AUTHOR]
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- 2023
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7. Risk of thromboembolism, recurrent hemorrhage, and death after warfarin therapy interruption for intracranial hemorrhage.
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Witt, Daniel M., Clark, Nathan P., Martinez, Kerri, Schroeder, Allison, Garcia, David, Crowther, Mark A., Ageno, Walter, Dentali, Francesco, Ye, Xiangyang, Hylek, Elaine, and Delate, Thomas
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THROMBOEMBOLISM , *HEMORRHAGE , *DISEASE relapse , *WARFARIN , *MORTALITY , *MEDICAL care , *MEDICAL decision making , *RETROSPECTIVE studies , *PATIENTS - Abstract
Background Whether and when to resume oral anticoagulant therapy for patients who survive warfarin-related intracranial hemorrhage (ICH) remains a dilemma lacking consensus recommendations and high-quality evidence to guide clinical decision making. Objective To determine the incidences of recurrent ICH, thrombosis, and death in relation to resumption or non-resumption of warfarin therapy during the 365 days after incident ICH. Methods We conducted a retrospective cohort study of adult patients in an integrated healthcare delivery system who were receiving warfarin therapy at the time of incident ( index ) ICH between 1/1/2000 and 12/31/2007 and survived to hospital discharge. The primary outcomes were recurrent ICH, thrombosis (stroke, systemic embolism, and venous thromboembolism), and all-cause mortality during the 365 days following index ICH. Patients were assigned to one of two groups defined by warfarin therapy resumption after the index ICH. Results There were 160 patients discharged from the hospital following warfarin-related index ICH; of these 54 (33.8%) resumed warfarin therapy and 106 (66.2%) did not. Recurrent ICH occurred in a numerically greater, but statistically non-significant, proportion of patients who did not resume warfarin therapy (7.6% vs. 3.7%, p = 0.497). Similarly, patients who did not resume warfarin had a three-fold higher (12.3% vs. 3.7%, p = 0.092) and approximately two-fold higher (31.1% vs. 18.5%, p = 0.089) rates of thrombosis and all-cause mortality, respectively, during follow up. Conclusion Resumption of warfarin therapy following warfarin-associated ICH appeared not to be associated with increased risk of recurrent ICH but trended toward reduced thrombosis and all-cause mortality. [ABSTRACT FROM AUTHOR]
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- 2015
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8. Thromboembolic and bleeding outcomes of low-intensity warfarin thromboprophylaxis following elective total hip arthroplasty.
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Clark, Nathan P., Cho, Stephanie E., Delate, Thomas, and Witt, Daniel M.
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THROMBOEMBOLISM , *HEMORRHAGE , *WARFARIN , *TOTAL hip replacement , *ORTHOPEDIC surgery - Abstract
Abstract: Background: Low-intensity warfarin is among the most frequently prescribed thromboprophylaxis regimens after major orthopedic surgery in the United States. This has been a source of controversy as the American College of Chest Physicians historically recommended standard intensity warfarin (INR 2–3) over low-intensity warfarin in this setting. The updated guidelines include low-intensity warfarin as a recommended option, but data evaluating this intervention has not kept pace with newer agents. Materials and Methods: We describe the risk of symptomatic venous thromboembolism and clinically relevant bleeding in a retrospective cohort of patients receiving low-intensity warfarin (INR 1.5 to 2.5) for six weeks after total hip arthroplasty. Outcomes were identified within a joint replacement registry and cross-verified by queries of electronic inpatient and outpatient databases and independently adjudicated by chart review. Results: 835 surgeries in 800 patients were included in the analysis. Mean patient age was 66years, 61.7% were female and 81.1% were prescribed mechanical prophylaxis in addition to warfarin. In the 90days after surgery, there were 13 cases of symptomatic venous thromboembolism (1.6% of surgeries) which included 10 cases of pulmonary embolism (1.2% of surgeries). The incidence of clinically relevant bleeding during warfarin therapy was 0.8% and one death unrelated to bleeding or venous thromboembolism occurred. Conclusions: Although warfarin produced low rates of clinically relevant bleeding and symptomatic venous thromboembolism, pulmonary embolism made up a greater proportion of events than anticipated. Low-intensity warfarin should be considered in future studies to identify the regimen that optimally balances risk of bleeding and symptomatic venous thromboembolism in a real world setting. [Copyright &y& Elsevier]
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- 2013
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9. Analysis of unfractionated heparin dose requirements to target therapeutic anti-Xa intensity during pregnancy
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Clark, Nathan P., Delate, Thomas, Cleary, Steven J., and Witt, Daniel M.
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HEPARIN , *PREGNANCY complications , *TARGETED drug delivery , *DRUG dosage , *CARDIOVASCULAR disease treatment , *THROMBOSIS , *CARDIOVASCULAR disease prevention , *PLACENTA , *MEDICAL informatics - Abstract
Abstract: Introduction: Unfractionated heparin (UFH) does not cross the placenta and has demonstrated utility in the prevention and treatment of thrombosis during pregnancy. Limited information is available to guide initiation and monitoring of therapeutic UFH targeting an anti-Xa concentration of 0.3-0.7 u/ml during pregnancy. The objective of this study was to describe UFH doses and monitoring strategies required to achieve and maintain therapeutic anti-Xa intensity in a cohort of women treated with UFH during pregnancy. Materials/Methods: Patients prescribed anti-Xa adjusted UFH during pregnancies occurring between January 1998 and March 2005 were included. Results: A total of 39 pregnancies for 37 women were identified. Unfractionated heparin doses were titrated to achieve a mid-interval anti-Xa level of 0.3-0.7 u/ml. Patients required a median 6.5 days and a mean UFH dose of 403.5 u/kg/day to achieve therapeutic anti-Xa levels. Most anti-Xa levels were within the target range (59%). The final UFH dose/kg required at the end of pregnancy was similar to that at the first therapeutic level (P>0.05); however some patients did require dose modification. Patients required a mean 14.1 anti-Xa determinations and 4.6 dose modifications during a mean 23.9 weeks of antenatal UFH therapy. Patient weight and UFH dose at the first therapeutic anti-Xa level were correlated (r=0.383, P=0.018). Conclusions: Pregnant women required a mean UFH dose of 403.5 u/kg/day to achieve midinterval anti-Xa levels of 0.3-0.7 u/ml. The required dose was correlated with patient weight and most anti-Xa measurements were within the target range. [Copyright &y& Elsevier]
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- 2010
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10. Assessment of the coding accuracy of warfarin-related bleeding events.
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Delate, Thomas, Jones, Aubrey E., Clark, Nathan P., and Witt, Daniel M.
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HEMORRHAGE risk factors , *MEDICAL coding , *WARFARIN , *DIAGNOSTIC errors , *NOSOLOGY , *HOSPITAL care - Abstract
Introduction Using International Classification of Diseases, 9th edition (ICD-9) diagnosis codes to identify potential warfarin-related bleeding events from administrative datasets is highly efficient but may be prone to identifying non-events. The objective of this study was to evaluate the ability of bleeding-related ICD-9 codes to identify true bleeding events in patients who were receiving warfarin therapy at the time of hospitalization. Methods This was a cross-sectional study conducted in an integrated healthcare delivery system. Anticoagulated patients aged ≥ 18 years and hospitalized between January 1, 2014 and March 31, 2014 were identified using administrative data queries. All hospitalizations were manually chart reviewed by a trained abstractor blinded to hospitalization diagnoses to assess for true bleeding events. Identification of the presence or lack of bleeding-related ICD-9 diagnosis code(s) for each hospitalization was then performed. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated for each ICD-9 code present. Results There were 486 hospitalizations in 468 anticoagulated patients with 57 true bleeding events identified. Patients had a mean age of 73.4 years and 50% were female. For codes in the principal position, sensitivity, specificity, PPV, and NPV were 7.0%, 99.8%, 80.0%, and 89.0%, respectively. For codes in any position, sensitivity, specificity, PPV, and NPV were 94.7%, 90.9%, 58.1%, and 99.2%, respectively. For major bleeding, sensitivity, specificity, PPV, and NPV were 100%, 83.1%, 14.0%, and 100%, respectively. Conclusions While the absence of a bleeding ICD-9 code reliably ruled-out hospitalization for warfarin-related bleeding, bleeding ICD-9 codes in the principal position were rarely used and undesirable false positive rates were identified when ICD-9 codes when recorded in any position and for major bleeding. Manual chart review is recommended to validate bleeding events from administrative data. [ABSTRACT FROM AUTHOR]
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- 2017
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11. Clinical outcomes of dabigatran use in patients with non-valvular atrial fibrillation and weight >120 kg.
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Coates, Jamie, Bitton, Emily, Hendje, Ashley, Delate, Thomas, Olson, Kari L., Knowles, Carla, Ly, Sara, Fink, Kristen M., and Clark, Nathan P.
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TREATMENT effectiveness , *ATRIAL fibrillation , *ISCHEMIC stroke , *DABIGATRAN , *MORTALITY - Abstract
Patients with obesity were underrepresented in studies evaluating the safety and effectiveness of direct oral anticoagulants (DOAC) in patients with non-valvular atrial fibrillation (NVAF). This study compared clinical outcomes in patients with NVAF and weighing >120 kg and ≤120 kg who were receiving dabigatran. This retrospective, matched, longitudinal cohort study included patients from three integrated healthcare delivery systems. Patients ≥18 years of age with NVAF were included if between September 1, 2016 and June 30, 2019 they received dabigatran. Patients >120 kg and ≤120 kg were matched up to 1:6 on age, sex, and CHA 2 DS 2 -VASc score. Data were extracted from administrative databases. The primary outcome was a composite of ischemic stroke, clinically-relevant bleeding, systemic embolism, and all-cause mortality. Multivariable regression analyses were performed. 777 and 3522 patients >120 kg and ≤120 kg, respectively, were matched. The >120 kg group tended to be younger with a higher burden of chronic disease. There was no difference between groups in the composite outcome (adjusted hazard ratio [AHR] 1.10, 95% confidence interval 0.89–1.37) or individual components of the composite. A subanalysis of clinically-relevant bleeding identified that patients >120 kg were at a greater risk of gastrointestinal bleeding (AHR 1.44, 95% CI 1.01–2.05). In patients with NVAF and >120 kg, dabigatran use was associated with a small increased risk of gastrointestinal bleeding but no differences in stroke, mortality or clinically-relevant bleeding. These findings suggest that dabigatran use is reasonable in patients with NVAF and weight >120 kg. • DOAC use in patients >120 kg creates the potential for poor clinical outcomes • Real-world data on DOAC use in patients >120 kg are limited • Overall, dabigatran's outcomes were equivalent between patients ≤ & >120 kg • Patients >120 kg had small increased risk of gastrointestinal bleed • Dabigatran use in patients >120 kg is reasonable [ABSTRACT FROM AUTHOR]
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- 2021
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12. Temporal trends in first-line outpatient anticoagulation treatment for cancer-associated venous thromboembolism.
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Delate, Thomas, Charlu, Malti, Zhu, Shiyun, Pai, Ashok, Clark, Nathan P., Witt, Daniel M., King, Jackson M., and King, Jordan B.
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THROMBOEMBOLISM , *ANTICOAGULANTS , *HEPARIN , *WARFARIN , *THERAPEUTICS - Abstract
First-line treatment and secondary prevention of venous thromboembolism (VTE) in patients with cancer consisted, historically, of unfractionated heparin or low-molecular weight heparin (LMWH). With recent clinical trials of direct oral anticoagulants (DOAC) showing similar efficacy as LMWH, little is known about anticoagulant prescribing patterns in patients with cancer and a VTE. This study characterized the temporal trends in first-line outpatient anticoagulation therapy for cancer-associated VTE. This retrospective cohort study of patients who were hospitalized for a cancer-associated venous thromboembolism (VTE) between 01/01/2000 and 10/31/2017 identified patients from the cancer registries at two regions of an integrated healthcare delivery system. The primary outcome was the trend in age- and sex-adjusted rates of first-line anticoagulant therapy during the 30 days post-hospital discharge. Therapies were categorized as 1) injectable LMWH monotherapy, 2) warfarin ± injectable, 3) injectable fondaparinux monotherapy, or 4) DOAC ± injectable. Overall, 9816 patients were included with a mean age of 66 ± 13 years and 54% were female. From 2000 to 2003, warfarin ± injectable was used in ≈90% of cases. After 2003, there was a steady decline in warfarin use (25% in 2017) corresponding with increased LMWH use: 11% in 2003 to 55% in 2017. The DOAC ± injectable use has rapidly increased from <1% in 2014 to 20% in 2017. From 2000 to 2017, first-line anticoagulant therapy for cancer-associated VTE has experienced a substantial increase in LMWH and DOAC use with a resultant decline in warfarin use. • Historically, cancer-associated VTE was treated with LMWH or UFH. • From 2000 to 2017, first-line LMWH and DOAC use increased while warfarin decreased. • DOAC and LMWH cost-effectiveness analyses compared to warfarin should be conducted. [ABSTRACT FROM AUTHOR]
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- 2020
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13. Adherence to and persistence with direct oral anticoagulant therapy among patients with new onset venous thromboembolism receiving extended anticoagulant therapy and followed by a centralized anticoagulation service.
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Packard, Anne, Delate, Thomas, Martinez, Kerri, and Clark, Nathan P.
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ANTICOAGULANTS , *THROMBOEMBOLISM - Abstract
Extended direct oral anticoagulant (DOAC) therapy may be required for patients with a venous thromboembolism (VTE); thus, DOAC adherence may impact the risk of recurrent VTE or bleeding. This was a retrospective cohort study. Adult patients with a VTE who were initiated on a DOAC between January 1, 2010 and December 31, 2017 for a cumulative >90 days of therapy were included. Adherence, measured with the proportion of days covered (PDC), was assessed during the six, 12, and 18 months after initiation. Patients were assigned to PDC ≥ 80% (adherent) or PDC < 80% (non-adherent) groups during the 1- to 6-month follow-up period. Rates of recurrent VTE and hemorrhagic events were compared between the groups. A total of 305 patients were included. The mean PDC were 96.0% (±8.0%), 94.7% (±8.2%), and 94.4% (±7.7%) during the 6-, 12-, and 18-month follow-ups, respectively, with 17 (5.6%) and 288 (94.4%) patients classified as non-adherent and adherent, respectively. Patients in the non-adherent group were more likely to have had a recurrent VTE during the 1- to 6-month (11.8% vs. 1.0%, p = 0.007) and 1- to 12-month follow-ups (16.6% vs. 3.6%, p = 0.030). There were no statistically significant differences between the groups in the rates of bleeding during any follow-up periods (all p > 0.05). In patients who had >90 days of initial DOAC therapy, adherence to DOAC therapy was high throughout the 18-month follow-up while DOAC non-adherence (i.e., PDC < 80%) increased the risk of recurrent VTE. • The consequences of DOAC adherence/non-adherence in patients with VTE are not well-studied. • DOAC non-adherence was associated with recurrent VTE. • DOAC adherence was not associated with an increased risk of bleeding. [ABSTRACT FROM AUTHOR]
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- 2020
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14. Effect of increased time in the therapeutic range on atrial fibrillation outcomes within a centralized anticoagulation service.
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Phelps, Elise, Delate, Thomas, Witt, Daniel M., Shaw, Paul B., Mccool, Kathleen H., and Clark, Nathan P.
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ANTICOAGULANTS , *ATRIAL fibrillation treatment , *THROMBOEMBOLISM , *WARFARIN , *DRUG therapy , *HEMORRHAGE treatment - Abstract
Background Clinical pharmacy anticoagulation services have improved the quality of anticoagulant therapy and are associated with lower rates of bleeding and thromboembolism compared to usual care. Several studies have found that higher time-in-therapeutic range (TTR) during warfarin therapy is associated with better warfarin outcomes. However, whether increasing TTR over time within an established anticoagulation service is associated with further reduction in bleeding and thromboembolic outcomes is unknown. Methods This was a retrospective cohort study of patients with atrial fibrillation conducted at an integrated healthcare delivery system with a centralized, pharmacist-managed anticoagulation service. Clinical outcomes (clinically-relevant bleeding, ischemic stroke or systemic embolism, and all-cause mortality) and TTR were compared between two distinct time periods: 1/1/2006 through 12/31/2007 (control group) and 1/1/2012 through 12/31/2013 (observation group) with regression modeling to adjustment for potential confounders. Results There were 3641 and 4764 patients in the control and observation groups, respectively. The mean age was 74.3 years and 54.4% of the cohort was female. Mean TTR was higher in the observation group (70.5% vs. 63.4%, p < 0.001). The composite outcome of clinically-relevant bleeding, thromboembolism and all-cause mortality occurred in 4.6% and 3.6% of the control and observation groups, respectively (adjusted odds ratio = 0.69; 95% confidence interval 0.54–0.87). Individual rates of stroke/systemic embolism and all-cause mortality were each lower in the observation group (both p < 0.05) while clinically-relevant bleeding was not significantly different (p = 0.256). Conclusion Increased TTR within a clinical pharmacy anticoagulation management service was associated with a lower risk of the composite outcomes of bleeding, thromboembolism and death in a large atrial fibrillation population receiving warfarin. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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15. The Budding Yeast Ubiquitin Protease Ubp7 Is a Novel Component Involved in S Phase Progression.
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Böhm, Stefanie, Szakal, Barnabas, Herken, Benjamin W., Sullivan, Meghan R., Mihalevic, Michael J., Kabbinavar, Faiz F., Branzei, Dana, Clark, Nathan L., and Bernstein, Kara A.
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UBIQUITIN , *BUDDING (Zoology) , *PROTEOLYTIC enzymes , *DNA damage , *CANCER prevention , *DNA repair - Abstract
DNAdamage must be repaired in an accurate and timely fashion to preserve genome stability. Cellular mechanisms preventing genome instability are crucial to human health because genome instability is considered a hallmark of cancer. Collectively referred to as the DNA damage response, conserved pathways ensure proper DNA damage recognition and repair. The function of numerous DNA damage response components is fine-tuned by posttranslational modifications, including ubiquitination. This not only involves the enzyme cascade responsible for conjugating ubiquitin to substrates but also requires enzymes that mediate directed removal of ubiquitin. Deubiquitinases remove ubiquitin from substrates to prevent degradation or to mediate signaling functions. The Saccharomyces cerevisiae deubiquitinase Ubp7 has been characterized previously as an endocytic factor. However, here we identify Ubp7 as a novel factor affecting S phase progression after hydroxyurea treatment and demonstrate an evolutionary and genetic interaction of Ubp7 with DNA damage repair pathways of homologous recombination and nucleotide excision repair. We find that deletion of UBP7 sensitizes cells to hydroxyurea and cisplatin and demonstrate that factors that stabilize replication forks are critical under these conditions. Furthermore, ubp7 cells xhibit an S phase progression defect upon checkpoint activation by hydroxyurea treatment. ubp7Δ mutants are epistatic to factors involved in histone maintenance and modification, and we find that a subset of Ubp7 is chromatin-associated. In summary, our results suggest that Ubp7 contributes to S phase progression by affecting the chromatin state at replication forks, and we propose histone H2B ubiquitination as a potential substrate of Ubp7. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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16. Thrombophilia testing patterns amongst patients with acute venous thromboembolism.
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Meyer, Melissa R., Witt, Daniel M., Delate, Thomas, Johnson, Samuel G., Fang, Margaret, Go, Alan, and Clark, Nathan P.
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VENOUS thrombosis treatment , *THROMBOEMBOLISM , *HYPERCOAGULATION disorders , *RETROSPECTIVE studies , *COMPARATIVE studies - Abstract
Background Thrombophilia testing has limited value in determining the selection and duration of anticoagulation therapy for venous thromboembolism (VTE), yet is commonly performed. This study describes the patterns and appropriateness of thrombophilia testing in a large cohort of patients with acute VTE. Materials and methods This was a retrospective study of a random sample of patients with a validated diagnosis of acute VTE diagnosed between January 1, 2004 and December 31, 2010. Events were identified from administrative data and verified via manual review. Patients were grouped by thrombophilia testing status and compared on patient characteristics and thrombophilia testing results and appropriateness. Results Of 1314 patients with validated VTE, 315 (24%) underwent thrombophilia testing, 62 (20%) of whom had ≥ 1 positive test. Tested patients were younger and more likely to have had a family history of VTE. Factor V Leiden (17%) and prothrombin G20210A mutation (4%) were the most commonly detected thrombophilias. Only 31 (10%) of tested patients met eligibility criteria for thrombophilia testing (i.e., at least one strong thrombophilic risk factor present) and were tested at least 90 days following unprovoked index VTE. Conclusions Thrombophilia is commonly evaluated in patients without a clear indication for testing and during times where results may be unreliable. Future studies are needed to assess interventions aimed at reducing inappropriate thrombophilia testing without adversely affecting patient outcomes. [ABSTRACT FROM AUTHOR]
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- 2015
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17. Thromboembolic and Bleeding Outcomes of Extended Duration Low-Intensity Warfarin Following Elective Total Knee Arthroplasty.
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Cho, Stephanie E., Delate, Thomas, Witt, Daniel M., and Clark, Nathan P.
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THROMBOEMBOLISM , *HEMORRHAGE , *WARFARIN , *TOTAL knee replacement , *DISEASE incidence , *HEALTH outcome assessment - Abstract
The purpose of this study was to describe the incidence of symptomatic venous thromboembolism (VTE), clinically-relevant bleeding, and death among a real-world population receiving warfarin prophylaxis targeting an international normalized ratio (INR) of 1.5 to 2.5 for four weeks following total knee arthroplasty (TKA). Materials and Methods This retrospective, observational study included patients receiving warfarin following a TKA between August 1, 2005 and July 31, 2009 identified in the Kaiser Permanente Total Joint Replacement Registry. Patients 18years, receiving warfarin for another indication, or without continuous KPCO membership during the study period were excluded. Results There were 1487 patients with TKA included in the analysis. Mean patient age was 67.7years and 61.7% were female. The median percent of time in therapeutic INR range during follow-up was 55% (interquartile range=35%-75%). Nineteen cases of symptomatic VTE [1.3%; 95% confidence interval (CI) 0.8%-2.0%] including ten pulmonary emboli (PE) (0.7%) were identified within 90days of surgery. Clinically-relevant bleeding occurred in 1.7% (95% CI 1.1%-2.5%) of patients during warfarin prophylaxis and there were no deaths within 90days of surgery. Conclusions The rates of symptomatic VTE and clinically-relevant bleeding following TKA in patients receiving warfarin prophylaxis with a target INR of 1.5 to 2.5 were low. Additional studies should include low-intensity warfarin to identify the regimen that optimally balances risks of bleeding and symptomatic VTE after major orthopedic surgery. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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18. Effect of warfarin on intracranial hemorrhage incidence and fatal outcomes.
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Witt, Daniel M., Delate, Thomas, Hylek, Elaine M., Clark, Nathan P., Crowther, Mark A., Dentali, Francesco, Ageno, Walter, Martinez, Kerri D., and Garcia, David A.
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CEREBRAL hemorrhage treatment , *WARFARIN , *DISEASE incidence , *CHRONIC diseases , *HEALTH outcome assessment , *CONFIDENCE intervals - Abstract
Abstract: Introduction: Avoiding intracranial hemorrhage (ICH) during warfarin therapy is critical but little is known about factors that affect warfarin-related ICH outcomes. We aimed to define the impact of warfarin on ICH incidence rates and to identify baseline clinical characteristics of patients who experienced ICH and factors associated with fatal ICH. Materials and Methods: The primary outcome of this retrospective cohort study was the incident ICH rate per 10,000 person-years for patients receiving and not receiving warfarin therapy. Cox proportional hazards modeling was used to adjust for potential confounding factors in assessment of the association of warfarin with fatal ICH. Results: A total of 1348 patients with incident ICH, 259 (19%) who were receiving warfarin therapy, were included. The incident ICH rates were 74/10,000 (warfarin) and 5/10,000 (non-warfarin) person-years (p<0.001). Warfarin patients were older and carried a higher burden of chronic disease. The unadjusted hazard ratio (HR) for fatal ICH was 1.64 (95% confidence interval [CI] 1.31-2.05) for warfarin patients compared to non-warfarin patients. However, the HR was no longer significant after adjustment for confounding variables (1.10; 95% CI 0.84-1.42). An INR greater than 3.5 at presentation doubled the adjusted risk for fatal ICH with warfarin therapy. Subarachnoid and subdural ICHs were less likely to be fatal than other ICH types, and each year increase in age was associated with 4% increased risk of fatal ICH. Conclusions: Although warfarin use increases the rate of incident ICH, other factors impact the risk of fatal ICH, even among anticoagulated patients. [Copyright &y& Elsevier]
- Published
- 2013
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19. Nonadherence with INR Monitoring and Anticoagulant Complications.
- Author
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Witt, Daniel M., Delate, Thomas, Clark, Nathan P., Garcia, David A., Hylek, Elaine M., Ageno, Walter, Dentali, Francesco, and Crowther, Mark A.
- Subjects
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ANTICOAGULANTS , *INTERNATIONAL normalized ratio , *THERAPEUTIC complications , *DRUG therapy , *WARFARIN , *THROMBOSIS , *REGRESSION analysis - Abstract
Abstract: Introduction: This study tests the hypothesis that nonadherence with INR monitoring is associated with an increased risk for warfarin-related bleeding and thrombosis and describes patient characteristics associated with INR monitoring nonadherence. Materials and Methods: This was a retrospective, longitudinal, matched cohort study wherein patients were categorized into adherent and nonadherent cohorts; adherent patients were matched 2:1 to nonadherent patients. The primary study endpoint was the first occurrence of bleeding or thromboembolism. Multivariate logistic regression modeling identified patient characteristics associated with INR monitoring adherence or nonadherence. Results: A total of 4995 and 2544 patients contributed 10729 and 5385 patient-years of warfarin therapy in the adherent and nonadherent groups, respectively. The rate of thromboembolic events during follow up was higher in the nonadherent group than in the adherent group (0.95% vs. 0.62% per patient-year, respectively; p=0.019) and nonadherence to INR monitoring was associated with a moderately higher risk of thromboembolism (adjusted Hazard Ratio=1.51; 95% confidence interval=1.04 – 2.20). The difference in bleeding between the two groups was not statistically significant. Conclusions: Repeatedly missing INR tests is an easily identified clinical parameter that is associated with moderately increased risk for thromboembolism in patients taking chronic warfarin therapy. Clinicians should carefully consider the underlying thromboembolic risk and extent of nonadherence when weighing the benefits of continued warfarin therapy for a given patient. [Copyright &y& Elsevier]
- Published
- 2013
- Full Text
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